A system called a thin client is known. In the thin client system, the system is configured such that a client terminal only has minimal functions to manage a resource such as an application, a file, or the like in a server.
The thin client system functions as if the client terminal performs processes as a main body, or stores data, while actually displaying the processing result performed by the server or the data stored in the server on the client terminal.
As described above, when screen data which is displayed on the client terminal is transmitted between the server and the client terminal, a screen update is generated according to operations. When the screen update is generated in the thin client system, differential screen data with respect to before and after the screen update is transmitted to the client terminal from the server. Here, for example, when a Web page is displayed in a Web browser, and when the Web page is vertically long, only a portion of the Web page is displayed on a display region of the Web browser. At this time, when operational information for scrolling the Web page is transmitted to the server from the client terminal, the differential screen data according to a scroll amount is transmitted with respect to the remaining portion of the Web page.
For example, at the time of displaying the Web page by the Web browser, when the display size of the Web page exceeds the screen size of the client terminal, the Web page may be displayed on the screen by narrowing the size to a portion of the Web page. At this time, when the remaining portion which is not displayed on the screen is browsed, after the scrolling operation which is received by the client terminal is notified to the server, the update screen after the scrolling is transmitted to the client terminal from the server as a difference. The thin client system of the related art is, for example, disclosed in Japanese Laid-open Patent Publication No. 6-214533, Japanese Laid-open Patent Publication No. 2004-349965, and Japanese Laid-open Patent Publication No. 2008-40529.